1. Field of the Invention
The present invention relates in general to a control apparatus for controlling starting of an engine of a hybrid vehicle, and more particularly to techniques for rapidly starting an internal combustion engine of a hybrid vehicle including the engine and an electric motor as vehicle drive power sources, when the engine is started in a motor drive mode of the hybrid vehicle in which the electric motor is used as the vehicle drive power source, without an output of the engine.
2. Discussion of Prior Art
JP-A-2006-213149A discloses a hybrid vehicle drive system including a continuously-variable transmission portion operable as an electrically controlled continuously-variable transmission which has an engine, and a first electric motor, a second electric motor and a differential mechanism that are disposed between the engine and an output shaft, and which is selectively switchable by releasing and engaging actions of coupling devices, between a continuously-variable shifting state in which the continuously-variable transmission portion is able to perform an electrically controlled continuously-variable shifting operation, and a step-variable shifting state in which the continuously-variable transmission portion is not able to perform the electrically controlled continuously-variable shifting operation. A control apparatus for this hybrid vehicle drive system is arranged such that a selected one of an operation to switch the shifting state of the electrically controlled continuously-variable transmission and an operation to start the engine is implemented prior to the other if the switching operation of the shifting state and the starting operation of the engine would otherwise overlap each other.
The control apparatus disclosed in the above-identified publication implements one of the switching operation of the shifting state and the engine starting operation prior to the other, if these switching and engine starting operations overlap each other. If the switching operation of the shifting state is implemented prior to the engine starting operation, for example, the engine speed is raised and started only after completion of the switching operation of the shifting state of the continuously-variable transmission portion which takes a relatively long time. In this case, therefore, a rise of the vehicle drive torque generated by the drive system is delayed with respect to a moment of rise of the drive torque expected by the vehicle operator.